Butadiene-cobalt carbonyl hydride adduct



Patented June I7, 1952 BUTADIENE-COBALT CARBONYL HYDRIDE ADDUCT William W. Prichard, Wilmington, Del., assignmto E. I. du Pont :de Nemours & Company,

Wil-

mington, Del., a corporation of Delaware No Drawing. Application October 14, 1947. Serial No. 779,837

8 Claims.

This invention relates to new organic metallic compounds and more particularly to new organic cobalt compounds.

Butadiene has been reacted with iron pentacarbonyl to give a product to which was assigned the :formula C4 HeFe(CO)a in which a mole oi butadiene has replaced two CO groups of the pentacarbonyl. [Reihlen et al., Ann., 482, 161 (1930).]

This invention has as an object the preparation of a new organic compound of cobalt. A further object is a process for the preparation of such a compound. Another object is a hydrogenation process using said compound. A still further object is a carbonylation process using such compound. Other objects will appear hereinafter.

These objects are accomplished by the following invention wherein a new liquid compound of butadiene with cobalt carbonyl hydride is produced by reacting butadiene with cobalt carbonyl [Coz(CO)s] in the presence ofa secondary alcohol under superatmospheric pressure and at a temperature within the range of 50 to 200 C. Other phases of the invention include those wherein the new organocobalt compound is employed as a hydrogenation catalyst in the hydrogenation of carboxylic acid anhydrides to the corresponding aldehyde dicarboxylates, and that wherein it is used as a catalyst in the introduction of carbonyl groups into oleflnic hydrocarbons by reaction with carbon monoxide and hydrogen.

In a more detailed and preferred practice of the invention a molal excess of butadiene is reacted, at a temperature within the range 100 to 150 0., with a molal amount of cobalt car bonyl [CO2(CO')8] in the presence of at least a molal amount of a saturated non-aromatic monohydric secondary alcohol under a pressure within the range of 100 to 150 atmospheres and the resulting butadiene-cobalt carbonyl hydride adduct formed is isolated in an inert atmosphere by distillation.

The following example illustrates the invention.

Example I A silver-lined shaker tube of 400 cc. capacity was charged with 30.6 g. (0.0895 mole) of Coi(CO)a and 100 g. (1.67 moles) of isopropanol.

The tube was pressured to 100 atmospheres with I solvent, the pressure was lowered to 2 mmuand 11.2 g. of orange-red liquid butadiene-cobalt carbonyl hydride adduct distilled and was collected at 32-33 C. under this pressure. The product reacted rapidly with the oxygen of the air to give a black tarry mass. It was, however,

stable at room temperature under a blanket of nitrogen, but at 55-60 C. it began to decompose even in the absence of air. It reacted vigorously with concentrated sulfuric or nitric acid to yield water-soluble and gaseous products. Analyses showed a cobalt content of 25.58 and 25.88% (calculated for C'aHrO4CO2CO, 26.11 Analysis by the Orsat technique of the sulfuric acid decomposition products gave the following:

Per cent C4 hydrocarbons, mostly butene 17.2 Carbon oxides, mostly carbon monoxide 69.8

i. e. a ratio of carbon oxides to 0'4 hydrocarbons of 4 to 1. From the physical and chemical properties of the compound the probable molecular formula is CaHrOuCO.

Although the invention has been illustrated with isopropanol, saturated monohydric secondary alcohols in general can be employed including isopropanol. secondary butanol, pentanol 2. pentanol-Zi. mixtures of pentanol-2 and -3, cyclohexanol, etc. Secondary saturated monohydric alcohols aliphatic in character. 1. e. nonaromatic, are preferred. The process is effective with other hydrogen donors including hydrogen, methanol and other primary alcohols, etc.

The relative proportions of the reactants can be varied widely although it is ordinarily desirable to employ two moles of butadiene with at least one mole, but preferably from 5 to 40 moles. of secondary alcohol per mole of cobalt carbonyl, ECoflCOhl. It is desirable to use a molal excess of the secondary alcohol since this, in addition to being the hydrogen donor, also serves suitably as the solvent. The molal ratios of hutadienezcobalt carbonyltsecondary alcohol most preferred are those within the range 2:1:5 to 3:1:40 since these usually. give optimum results.

The temperatures employed in the practice of the invention are generally within the range of about 50 to 200 0., preferably to C. Superatmospheric pressures which are used ordinarily exceed 50 atmospheres and for optimum results, pressures within the range of 100 to 150 atmospheres are employed. Because of the tendency of cobalt carbonyl to decompose at elevated temperatures to give cobalt metal and carbon monoxide, it is usually desirable, though not essential, to impress a carbon monoxide pressure of 100 to 500 atmospheres under the particular conditions of operation in order to repress the decomposition of cobalt carbonyl.

The new compound of this invention is a new and unusual type 01 hydrogenation catalyst in that it cnrtalyzes the reduction or mturated carboxylic acid-anhydrides to the corresponding aldehyde dicarboxylates in an atmosphere of carbon monoxide and hydrogen, and that it is also soluble in common organic solvents. This phase 01 the invention is illustrated in Example II below.

Example [I A silver-lined pressure vessel of 400 cc. capacity was charged with 100 parts of acetic anhydride and 2 parts of butadiene-cobalt carbonyl hydride adduct prepared in accordance with the procedure of the above example. The vessel was closed, pressured to 200 atmospheres with hydrogen, and then to 600 atmospheres with carbon monoxide. Agitation was started and the vessel was heated to 130 C. and maintained at this temperature for 4 hours. A pressure drop from 805 to 645 atmospheres was noted during this period. After cooling the tube, a homogeneous solution was recovered which, when heated on a steam bath, changed to a purple color characteristic of cobalt acetate in acetic acid solution. This product was washed thoroughly with water to decompose any unchanged anhydride and a water-insoluble portion, 13 parts, separated. This was shown to be ethylidene diaoetate, as evidenced by the boiling point of 59-62" C./9 mm. and the preparation therefrom of a 2, l-dinitrophenylhydrazone melting at 163--l64 C. identical with the corresponding deri ative of acetaldehyde.

By the above general procedure, substitution of propionic anhydride for the acetic anhydride gave propylidene dipropionate. Similarly anhy drides up to hexanoic anhydride may be used. It is preferred to use the anhydrides of saturated aliphatic monocarboxylic acids, particularly of the alkanoic acids of up to six carbon atoms, since these are more readily available and, in general, give higher yields of alkylidene dialkanoiates.

The compound of the invention is also an active catalyst for the introduction of carbonyl groups into olefinic hydrocarbons. For example, with this catalyst and in the presence of carbon monoxide and hydrogen, cyclohexene can be readily converted to hexahydrobenzaldehyde as is illustrated in detail below.

Example III A silver-lined pressure vessel of 400 cc. capacit was charged with 100 parts of cyclohexene and 1 part of butacliene-cobalt carbonyl hydride adduct described in Example I. The vessel was closed, pressured to 200 atmospheres with hydrogen, and then to 600' atmospheres with carbon monoxide. Agitation was started and the vessel was heated to 150 C. and maintained at this temperature throughout the reaction. A pressure drop of 415 atmospheres was noted during 14 hours of reaction. The crude product, 129 parts or 95% of the theoretically possible weight, was distilled. No unchanged cyclohexene was recovered therefrom and the product was found to consist solely of hexahydrobenzaldehyde, its dimer and trimer.

Under the same hydrogen and carbon monoxide pressures as above, butadiene with the new compound of the invention as catalyst gave, after 1.25 hours reaction at 135 C., a 55% yield of saturated S-carbon monoaldehydes which consisted of approximately eq al Darts 01 n-valeraldehyde and methylethylacetaldehyde. This is described in more detail and claimed in Brooks ill) application Serial Number 785,799, flled;Novemher 13, 1947.

7 Other oleflns such as ethylene, propylene, isobutylene, etc., can likewise be converted to aldehydeswith the new compound of this invention ascatalyst.

The foregoing detailed description has been given. for; clearness. of understanding only and no unnecessary limitations are to be understood therefrom. The invention is not limited to the exact details shown and described, for obvious modifications will occur to those skilled in the art.

What is claimed is:

l. A process for the preparation 01 a new compound of cobalt which comprises heating cobalt carbonyl with from2 to 3 moles. her mole otcobalt carbonyl, of butadiene and from lto. 40 moles. per mole of cobalt; carbonyl, of 1501 101381101. at -150 C. under a carbon monoxide pressure of 100 to 500 atmospheres.

2. A process wherein cobalt carbonyl is heated at Ell-200 C. with from two to three moles, per mole of cobalt carbonyl, of butadiene and from one to forty moles, per mole of cobalt carbonyl, of a saturated non-aromatic monohydric secondary alcohol under a. carbon monoxide pressure of 100 to 500 atmospheres.

3. A process wherein cobalt carbonyl is heated at 50-200" 0. with from two to three moles, per mole of cobalt carbonyl, of butadiene and from one to forty moles, per mole of cobalt carbonyl, of a secondary, saturated, non-aromatic, monohydric alcohol under a pressure of at least 50 atmospheres.

4. A process wherein cobalt carbonyl is heated at 50-200 C. with butadiene and a secondary, saturated, non-aromatic. monohydric alcohol and the 'butadiene-cobalt carbonyl hydride adduct is isolated.

5. A process wherein cobalt carbonyl is heated at 50-200 C. with butadiene and a primary, saturated, non-arornatic, monohydric alcohol and the loittaldienewobalt carbonyl hydride adduct is iso- 6. A process wherein cobalt carbonyl is heated at 50-200 C. with butadiene and methanol and the butadiene-cobalt carbonyl hydride adduct is isolated.

'7. A process wherein cobalt carbonyl is heated with butadiene in the presence of a hydrogen donor of the class consisting of primary and secondary saturated, non-aromatic, monohydric alcohols and the butadiene-cobalt carbonyl hydride adduct is isolated.

8. A distillable liquid butadiene-cobalt carbonyl hydride adduct, boiling at 32-33 C. at a pressure of 2 mm. of mercury, and of the molecular formula CBH7O4C0.

WILLIAM W. PRICHARD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,637,281 Schatz July 26, 1927 2,211,624 Loder et al. l Aug. 13, 1940 2,358,048 Bitler ct a]. Sept. 12, 1944 2,360,283 Rutherford Oct. 10, 1944 2,409,167 Veltman Oct. 8, 1946 2,429,501 Yale et a1 Oct. 21, 1947 

8. A DISTILLABLE LIQUID BUTADIENE-COBALT CARBONYL HYDRIDE ADDUCT, BOILING AT 32-33* C. AT A PRESSURE OF 2 MM. OF MERCURY, AND OF THE MOLECULAR FORMULA C3H7O4CO. 